The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Fiber optic links have been applied to both long distance telecommunications and shorter distance data communication links within an enterprise. These links consist of a detachable optical fiber, with an electro-optical terminal (E-O terminal) at each end. Frequently these are duplex links, including both transmitter and receiver functionality at each E-O terminal. The major components conventionally include: a laser (in particular a Vertical-Cavity Surface-Emitting Laser (VCSEL)), the driver circuit, which is conventionally an integrated circuit (I.C.), for driving the laser, a photodetector that receives the light and converts it to an electrical signal, an integrated circuit for amplifying and digitizing the signal detected by the photodetector, and a circuit board on which the semiconductor components would be mounted. Commonly, the laser and photodetector may be packaged in a first level package before mounting on the circuit board. The I.C.s may also be in a first level package before attaching to the circuit board. The circuit board also needs to include an electrical connector that allows it to be plugged into and have electrical communication with a host circuit board. The transceiver also usually includes an optical connector that allows an optical fiber to be attached and detached, and to be properly aligned with respect to the laser and photodetector when it is attached. Finally, there is a housing that generally covers and incorporates all components. Due to high reliability and environmental demands, E-O terminals involve several layers of packaging. A typical duplex E-O terminal, or transceiver, for data communication applications might be 1 centimeter wide by 6 centimeters long by 0.5 centimeters high. More recently, the same functionality is achieved with an Active Optical Cable (AOC) in which the fiber is permanently attached to both of the E-O terminal ends.
As the data rates associated with the transfer of video reaches 10-40 Gbps, there has been increased interest in developing fiber optic links for consumer applications. Transmission distances over copper are limited, and the copper cable is rather thick and inflexible. For consumer applications, cost considerations play a very important role, and so new approaches are required in order to simultaneously achieve the both performance and cost requirements. There is also an interest in incorporating fiber optic links inside of consumer electronics, such as but not limited to, laptops, tablets, televisions, or phones in order to eliminate the effect of electro-magnetic interference from high speed signals being transferred along copper wires. However, the use of fiber-optic links in these embedded applications also requires a very small size, i.e., a few millimeters on a side. Many of these links can be simplex links, with information travelling in only one direction, requiring only a transmitter E-O terminal at one end, and a receiver E-O terminal at the other end. The fiber can also be permanently attached, forming an AOC.